Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/073—Metallic material containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
  • C23C4/11—Oxides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
  • C23C4/126—Detonation spraying
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
  • C23C4/129—Flame spraying
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12049—Nonmetal component
  • Y10T428/12056—Entirely inorganic
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12063—Nonparticulate metal component
  • Y10T428/12139—Nonmetal particles in particulate component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12146—Nonmetal particles in a component

Definitions

• the invention relates to a process for thermal spraying a MCrAlY-based powder composition onto a surface of a substrate using a gaseous fuel-oxygen mixture in which sufficient oxygen in the fuel mixture is used to form Y2O3 from a substantial portion of yttrium (Y) in the powder composition and to form Al2O3 from a minor portion of the aluminum (Al) in the powder composition.
• Aluminide coatings were initially used to provide a corrosion resistant outer layer but such layer was observed to crack when subjected to mechanically or thermally induced strain.
• Another class of coatings developed was the MCrAlY overlay Coatings where M represents a transition metal element such as iron, cobalt or nickel. The coatings have been found to be more effective than the aluminide coatings in extending the useful life of alloy components in high temperature environments.
• a current problem with conventional MCrAlY coatings on superalloy substrates is interdiffusion of coating elements into the substrate and substrate elements into the coating after long times of high temperature exposure.
• the loss of coating aluminum to the substrate is noticed by an aluminide depletion layer in the coating.
• Certain substrate elements like titanium have been found to diffuse through the MCrAlY coating to the external surface oxide scale and to make said oxide scale less protective. It would be desirable to modify current MCrAlY coatings to reduce this interdiffusion effect.
• MCrAlY has overall been a successful class of coatings having good oxidation and corrosion resistance for superalloys, improvements have been made to the MCrAlY coatings.
• U.S. Patent No. 3,993,454 discloses coatings which are particularly suited for the protection of nickel and cobalt superalloy articles at elevated temperatures.
• the protective nature of the coatings is due to the formation of an alumina layer on the surface of the coating which serves to reduce oxidation/corrosion.
• the coatings contain aluminum, chromium, and one metal chosen from the group consisting of nickel and cobalt or mixtures thereof.
• the coatings further contain a small controlled percentage of hafnium which serves to greatly improve the adherence and durability of the protective alumina film on the surface of the coating.
• U.S. patent No. 4,585,481 discloses a similar coating except that yttrium and hafnium are used together along with silicon.
• Another object of the present invention is to provide a process for producing a MCrAlY-based coating using a detonation gun and wherein the coating has an oxide dispersion throughout.
• Another object of the present invention is to provide a MCrAlY-based coating where Y is substantially in the Y2O3 form and a minor amount of the Al is in the Al2O3 form.
• the invention relates to a process for producing a MCrAlY-based coating wherein M is selected from the group consisting of iron, cobalt, nickel and mixtures thereof, which comprises the thermal spraying, such as by detonation gun means, of a MCrAlY-based powder composition onto the surface of a substrate using a gaseous fuel-oxidant mixture comprising an oxidant and at least one combustible gas selected from the group of saturated and unsaturated hydrocarbons in which the atomic ratio of oxygen to carbon is between 1.045 to 1 and 1.10 to 1, preferably between 1.05 to 1 and 1.08 to 1, and most preferably about 1.06 to 1, and the coated layer having at least 70 percent of the yttrium component in the form of Y2O3 and up to 30 percent of the aluminum component in the form of Al2O3.
• the oxygen should be present in the coating in an amount of at least 1.5 weight percent, more preferably at least about 2.5 weight percent.
• the maximum amount of oxygen should not exceed 4 weight percent of the
• the detonation gun consists of a fluid-cooled barrel having a small inner diameter of about one inch.
• a mixture of oxygen and acetylene is fed into the gun along with a coating powder.
• the oxygen-acetylene fuel gas mixture is ignited to produce a detonation wave which travels down the barrel of the gun whereupon the coating material is heated and propelled out of the gun onto an article to be coated.
• U.S. Patent No. 2,714,563 discloses a method and apparatus which utilizes detonation waves for flame coating. The disclosure of this U.S. Patent No.
• 2,972,550 is incorporated herein by reference as if the disclosure was recited in full text in this specification.
• a second combustible gas may be used along with acetylene, such gas preferably being propylene.
• the use of two combustible gases is disclosed in U.S. Patent No. 4,902,539 which is incorporated herein by reference as if the disclosure was recited in full text in this specification.
• a feature of the present invention is that a higher aluminum concentration can be used in the MCrAlY-based powder composition since some of the aluminum will react with the oxygen from the fuel mixture to form Al2O3. It was found that the life per mil of coating thickness is essentially proportional to the amount of aluminum in the coating. Thus a coating with 12 weight percent aluminum would be expected to last 50 percent longer than a coating with 8 percent aluminum. Alternately, the higher aluminum coatings will be capable of higher temperature exposure for the same life per mil.
• the oxide phases generated with the gaseous fuel-oxidant mixture and the MCrAlY-based powder composition occurs such that the oxygen will react preferably with the metallic elements having the highest free energy of oxide formation of the components of the coating.
• Yttrium and aluminum have the highest free energy of oxide formation of the elements in the typical McrAlY alloy and since yttrium has a higher free energy of oxide formation than aluminum, the yttrium will be substantially converted to Y2O3, such as 90 weight percent or greater, and a minor portion of aluminum will be converted to Al2O3, such as less than about 30 weight percent for a typical MCrAlY composition and an oxygen content of about 2 percent.
• the oxide dispersion in the coating should be less than 15 volume percent, preferably less than 10 volume percent and at least greater than 4 volume percent.
• less than 30 percent by weight of the aluminum should be converted to Al2O3 and preferably less than 25 percent by weight should be converted to Al2O3.
• the coatings of this invention can be used as a single layer environmental MCrAlY-based coating or as an enhanced bondcoat for thermal barrier coatings.
• the powders for use in this invention are preferably powders made by the vacuum-melted argon-atomization process.
• the atomic ratio of oxygen to carbon in the gaseous fuel-oxidant mixture can be adjusted between 1.045 to 1 and 1.10 to 1.
• the greater the proportion of oxygen in the fuel will convert more of the aluminum to Al2O3.
• the coating produced can be heat treated to further stabilize the formation of the oxides.
• the heat treatment could be conducted at 800°C or above, preferably at 1000°C or above for a time period to substantially stabilize the formation of the oxides.
• the time period of the heating step could be from 2 to 10 hours, preferably from 3 to 5 hours.
• the MCrAlY powder composition of this invention could have chromium in an amount from 10 to 50 weight percent, preferably from 15 to 40 weight percent and most preferably from 17 to 30 weight percent, aluminum in an amount from 4 to 20 weight percent, preferably from 6 to 18 weight percent and most preferably from 7 to 16 weight percent, yttrium from 0.1 to 1.0 weight percent, preferably from 0.2 to 0.8 weight percent and most preferably from 0.2 to 0.6 weight percent, and balance being iron, cobalt, nickel or mixtures thereof.
• the combustible gas of the gaseous fuel-oxidant mixture for this invention could be at least one gas from the group consisting of acetylene (C2H2), propylene (C3H6), methane (CH4), methyl acetylene (C3H4), propane (C3H8), ethane (C2H6), butadienes (C4H6), butylenes (C4H8), butanes (C4H10), cyclopropane (C3H6), propadiene (C3H4), cyclobutane (C4H8), and ethylene oxide (C2H8O).
• the preferred fuel mixture would comprise acetylene gas alone or mixed with at least one other combustible gas such as propylene.
• an inert gas such as nitrogen could be added to the gaseous fuel mixture in an amount of 20 to 50, preferably 30 to 40 volume percent based on the volume of the combustible fuel and oxygen.
• the flow rate of the gaseous fuel-oxidant mixture can vary between 10 to 14, preferably between 11 to 13 cubic feet per minute and the fire rate can vary from 4 to 10, preferably 7 to 9 times per second.
• the powder feed rate in the barrel could vary between 5 to 35, preferably between 15 to 25 grams per minute. The parameters would be selected so that the desired amount of oxygen would be available to react with the aluminum and yttrium to form the amount of Al2O3 and Y2O3 desired in the final coating.
• Another method of producing the coating of this invention may be the high velocity oxy-fuel, including the so-called hypersonic flame spray coating processes.
• oxygen and a fuel gas are continuously combusted thereby forming a high velocity gas stream into which the powdered material of the coating composition is injected.
• the powder particles are heated to near their melting point, accelerated and impinged upon the surface to be coated. Upon impact, the powder particles flow outward forming overlapping thin, lenticular particles and splats.
• the oxygen to fuel ratio in cubic feet per hour should be between 9 to 1 and 4 to 1, preferably between 7 to 1 and 5 to 1.
• the oxygen to hydrogen ratio on the basis of moles of gas, should be greater than 0.5 to 1.
• the coating materials of this invention are ideally suited for coating substrates made of materials such as titanium, steel, aluminum, nickel, cobalt, alloys thereof and the like.
• Coating A made with a plasma torch with coaxial argon shielding
• Coating B made with a detonation gun (D-Gun) at atomic ratio of oxygen to carbon of 1.06 to 1.00 using the identical powder lot used for the plasma torch Coating A
• Coating C made with a detonation gun at atomic ratio of oxygen to carbon of 1.06 to 1.00 using a powder which was identical to the powder lot used in Coating A except that additional aluminum was added to compensate for the amount of metallic aluminum that would be converted to aluminum oxide during the detonation gun process.
• Three coatings were made using the aluminum-compensate powder with the detonation gun employing oxygen and propylene gas mixtures in varying proportions to produce different oxygen to carbon ratios.
• the coatings were on IN718 pins, and were heat treated and finished after coating and oxidation tested as described in Example 1.
• the coatings were initially very oxidation resistant, as shown by the data of Table 3 at 114 hours at 1900°F and 80 hours at 2000°F. At longer times, however, the coating has relatively high depletion values at both temperatures. At the 1.03:1 oxygen-carbon ratio the coating was more stable in long-term oxidation testing. At the 1.06:1 oxygen to carbon ratio the resultant coating had the best combination of low initial oxidation rate and long-term oxidation resistance.
• Coating C of Example 2 was chemically analyzed for its oxygen and carbon content (Table 4). Based on the chemical analysis of the coating, the amount of Y2O3 and Al2O3 were calculated assuming equilibrium and that all oxygen was converted to the most stable oxides.
• Coating C had a calculated total dispersed oxide content of 9.1 vol. percent.
• Table 4 Measured wt % Calculated Vol. % Coating Oxygen: Carbon Ratio Oxygen Carbon Y2O3 % Y in Y2O3* Al2O3 Al* % Al in Al2O3* C D-Gun 1.06:1 2.34 1.05 1.2 100 7.9 10.74 18.40 Baseline Plasma Coating -- 0.15 0.01 1.1 100.00 0 12.50 0 * percent by weight

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Coating By Spraying Or Casting (AREA)

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• 1995
  • 1995-06-23 DE DE69514156T patent/DE69514156T2/de not_active Expired - Fee Related
  • 1995-06-23 JP JP7179606A patent/JP3044182B2/ja not_active Expired - Fee Related
  • 1995-06-23 CA CA002152524A patent/CA2152524C/fr not_active Expired - Fee Related
  • 1995-06-23 CN CN95107093A patent/CN1068387C/zh not_active Expired - Fee Related
  • 1995-06-23 EP EP95109846A patent/EP0688885B1/fr not_active Expired - Lifetime
  • 1995-06-23 KR KR1019950016995A patent/KR100259482B1/ko not_active Expired - Fee Related
  • 1995-06-23 TW TW084106454A patent/TW493016B/zh not_active IP Right Cessation
• 1996
  • 1996-04-05 US US08/628,371 patent/US5741556A/en not_active Expired - Lifetime

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